1920.] 



Feeding Value of Silage. 



279 



of starch whicli, in a mixed diet containing an adequate supply 

 of ^dbuminoids, would have the same v^alue for simple 

 "maintenance" purposes a§ 10 j lb. of the silage. Taking 

 these figures as the basis, and the corresponding " maintenance 

 starch equivalents " for roots and hay of average quality, 

 the data given in the last two columns of the table are arrived at. 



In this connection it may be pointed out that although 

 silage in farm economy and feeding practice serves commonly 

 as a substitute for root crops, its only outstanding resemblance 

 to roots in feeding properties is its succulence. It is more 

 tibrous and less digestible than roots, and in chemical composi- 

 tion, apart from its high moisture-content, resembles the hay 

 that might alternatively have been made from the original 

 green fodder. 



The estimated " starch equivalents " range from 10*3 

 per cent, for the maize silage to 23*3 per cent, in the case of a 

 lucerne and seeds second-crop silage. The value in terms of 

 roots ranges from 1*12 to 2*54 tons of roots per ton of silage, 

 while in terms of hay the range is from Z'l to 476 tons of 

 silage equal to i ton of good hay. 



The wide range of variation thus indicated is due more 

 to the great differences in moisture-content of the silages 

 than to intrinsic differences in the feeding value of the actual 

 nutritive matter. If the silages are reduced to a comparable 

 basis of 70 per cent, of moisture (or 30 per cent, of dry matter) 

 the range of variation in starch-equivalent is only from 

 15*5 per cent, to 17*8 per cent. ; that is, the best is only about 

 15 per cent, better than the worst. In view of the assumptions 

 underlying these estimates it will be safest to conclude that, 

 so far as chemical analysis can furnish guidance, the various 

 silages had substantially the same feeding value apart from the 

 variations in moisture-content. This conclusion only holds 

 good if the silage is fed in a mixed diet which supplies sufficient 

 albuminoids for the needs of the animal. If the albuminoid 

 supply were scanty the silages containing the higher proportions 

 of albuminoids would have a higher intrinsic value than they 

 are credited with in the above estimates. 



Assuming 30 per cent, of dry matter, the average " starch- 

 equivalent " for the 17 samples is I7'05 per cent. One ton 

 of such average sUage would be equivalent for " maintenance " 

 purposes to i"85 tons of roots ; or 2 "87 tons of silage would be 

 equivalent to i ton of good meadow hay. These figures 

 bear out closely the opinion expressed by Mr. Arthur Amos 



u 2 



